A conventional carrier for chip mounting which has been used for many years is a metalized ceramic flat pack construction. While the ceramic has many good features, there are certain drawbacks to its use. For example, the ceramic does not have particularly good thermal conductivity properties, and thus often require innovative techniques for removal of heat. Also, the ceramic requires careful handling, especially before firing to prevent breakage. Moreover, ceramic requires several operations to form the necessary ceramic carrier, thus resulting in a fairly high cost.
There has been some effort to replace ceramic carriers with an organic carrier, such as glass-filled epoxy, which has characteristics similar to that of a circuit board, i.e., the same material. While certain of the drawbacks of the ceramic carrier are overcome, nevertheless such carriers have certain drawbacks, such as relatively poor conductivity and certain technological problems in forming the required fine line circuitry on the surface of the carrier for the connecting of the chip thereon and conveying the signals to and from the circuit board.
It is therefore a principal object of the present invention to provide a package for mounting an integrated circuit chip to a circuit board which includes a chip carrier having improved heat transfer properties and good electrical properties, including a floating ground plane.